Evaluation of calcium and vitamin D supplementation in bisphosphonate therapy

Objective: To assess the calcium and vitamin D intake of osteoporosis patients on bisphosphonate therapy. Design: Prospective study. Setting: Two independent pharmacies (Futrell Pharmacy Services, Jackson N.C., and McDowell's Pharmacy, Scotland Neck, N.C.) and one ambulatory care clinic (Scotland Neck Family Medical Center, Scotland Neck, N.C.) in eastern rural North Carolina from December 2005 to February 2006. Patients: 29 osteoporosis patients on bisphosphonate therapy. Interventions: Patients were assessed on calcium intake and counseled on the appropriateness of supplementation with bisphosphonate therapy. Main outcome measure: Degree to which osteoporosis patients on bisphosphonate therapy use concomitant calcium supplements. Results: Of the 29 patients surveyed, 17 patients were using calcium supplements during bisphosphonate therapy. Reasons cited for not using calcium included constipation (7 patients), polypharmacy (3), forgetfulness (1), and deemed unnecessary (1). Types of calcium supplements used were 71% calcium carbonate (12 patients), 24% calcium citrate (4), and 5% unknown (1). Calcium doses used were 500 mg/day (4 patients), and 1,000 mg/day (3), and 1,200-1,400 mg/day (13). Also, 13 patients were taking vitamin D in addition to their calcium, with 8 patients taking 400 IU and the rest 200 IU. Among the patients surveyed, 8 reported taking a proton-pump inhibitor, and 6 were taking calcium carbonate, which is not absorbed well in those taking agents that increase gastric pH. All patients separated their bisphosphonate dose from other medications and meals. Conclusion: Patients do not recognize the need to supplement calcium at the recommended dosage of at least 1,200 mg/day or 1,500 mg/day for postmenopausal women with osteoporosis along with vitamin D 400 IU for osteoporosis treatment while on bisphosphonate therapy.